Apr. 17, 1916 



Stearic Acid in Butter Fat 



103 



Table I. — Solubility of stearic acid, according to various investigators 



Investigator. 



Hehner and Mitchell (3, p. 323) 

 Emerson (2, p. 1754) 



Do 



Do 



Kreis and Hafner (5) 



Lewkowitsch (6, p. 164) 



Do 



Ruttan (8, p. 440) 



Approximate 



strength of 



alcohol. 



Per cent. 

 94.4 



95-5 



95- 

 94. 



95 



94. 



94. 



100 



Stearic add to 

 100 c. c. 



Gm. 

 O. 2 to O. 5 



•7 

 ■7 



•7 

 • 5 

 ■3 

 ■7 



Sattiration of 100 c. c. 

 at 0° C. 



Gm. 

 1400 to o. 1580 



• 1223 



• I 139 

 1035 



13 10 

 0814 

 1082 

 373 



1220 to 



0810 to 



PRELIMINARY WORK 



In view of what has been stated, the outlook for another investigation 

 was not promising, although Lewkowitsch's final arraignment of the 

 process was not published until nearly a year after the work was under- 

 taken. The subject was of sufficient importance, however, to warrant 

 additional study whatever the outcome. 



Apparatus. — To insure a uniform temperature for crystallization, a 

 tank was constructed of ^-inch lumber (20 inches long, 10 inches 

 wide, and 20 inches deep), lined with galvanized iron, provided with 

 a tight cover, and raised by legs to a convenient working height. 

 For icing, a basket (i3>2 by 6 by 18 inches) of galvanized screening 

 of "i^-inch mesh, holding probably 30 pounds of broken ice, was found 

 very satisfactory. The insulation of wood, together with the large 

 volume of water and ice, proved inadequate to meet the requirements 

 of the case, and it was necessary to install in one comer of the tank a 

 pump run by a motor, to keep the water in continuous circulation. With 

 this apparatus a constant temperature of about 0.1° C. was easily main- 

 tained (fig. 1,2). 



Several factors had to be considered in the selection of containers 

 in which the tests were to be conducted. They must be of a form, 

 size, and weight suitable for weighing the charge on analytical bal- 

 ances, easily held in position in the tank, and such that the alcoholic 

 solution could be removed while still in the tank, leaving the crystalline 

 residue. After numerous experiments with globe-shaped separatory 

 funnels and filtering tubes, 8-ounce sterilizer bottles were adopted 

 and have been found fairly satisfactory. The bottles are of narrow 

 cylindrical form (2 by 6^ inches) and are held in place in the 

 tank by pockets of wire screening, with only the rubber stopper and a 

 small portion of the neck projecting out of the water. The solution 

 is siphoned off by means of a small thistle tube (>^-inch bulb) having 

 a felt of absorbent cotton weighing 0.020 gm. supported by a glass 

 bead and covered with a piece of batiste. 



